1. Field of the Invention
The present invention relates to a liquid discharge head that discharges a desired liquid by the bubbles created by the application of thermal energy acting upon the liquid, and also, relates to the head cartridge and the liquid discharge apparatus using such liquid discharge head. More particularly, the invention relates to a liquid discharge head provided with the movable member which is displaceable by the utilization of the creation of bubbles, as well as to a head cartridge and a liquid discharge apparatus using such liquid discharge head.
Also, the present invention is applicable to a printer capable of recording on a recording medium, such as paper, thread, textile, cloth, leather, metal, plastic, glass, wood, and ceramics, among some others. the invention is also applicable to a copying machine, a facsimile equipment having communication systems, and an apparatus, such as a wordprocessor, which is provided with a printer. The invention is also applicable to a recording system for industrial use arranged complexly in combination with various processing apparatuses.
Here, in the specification of the present invention, the term xe2x80x9crecordxe2x80x9d means not only the provision of characters, graphics, and other meaningful images, but also, it means the provision of patterns or other images which do not present any particular meaning.
2. Related Background Art
There has been known the ink jet recording method, that is, the so-called bubble jet recording method in which the energy, such as heat, is given to ink to cause the change of states of ink which is accompanied by the abrupt voluminal changes (creation of bubbles), and ink is discharged from the discharge ports by the acting force based on this change of states, and then, the discharged ink is allowed to adhere to a recording medium for the formation of images. The recording apparatus using this bubble jet recording method is generally provided with the discharge ports for discharging ink; the ink flow paths communicated with the discharge ports; and the electrothermal transducing devices (elements) each arranged in each of the ink flow paths, serving as means for generating energy used for discharging ink as disclosed in the specifications of U.S. Pat. No. 4,723,129, and others.
In accordance with a recording method of the kind, it is possible to record high quality images at higher speeds in a lesser amount of noises. At the same time, with the head whereby to execute this recording method, it becomes possible to arrange the discharge ports for discharging ink in higher density, among many other advantages, hence obtaining recorded images in higher resolution with a smaller apparatus, and obtaining images in colors with ease as well. In recent years, therefore, the bubble jet recording method is widely utilized for many kinds of office equipment, such as printer, copying machine, facsimile equipment, and further, utilized for the textile printing system and others for the industrial use.
Now, along with the wider utilization of the bubble jet technologies and techniques for the products currently in use in many fields, there have been various demands increasingly more in recent years as given below.
In order to obtain images in higher quality, the driving condition is proposed anew so that the liquid discharge method or the like should be arranged to perform good ink discharges on the basis of the stabilized creation of bubbles that enables ink to be discharged at higher speeds. Also, from the viewpoint of the higher recording, there has been proposed the improved configuration of flow paths so as to obtain the liquid discharge head which is capable of performing in the liquid flow paths the higher refilling for the liquid that has been discharged.
Besides a head of the kind, an invention is disclosed in the specification of Japanese Patent Application Laid-Open No. 6-31918 (particularly, FIG. 3) in which attention is given to the back waves (the pressure directed in the direction opposite to the one toward the discharge ports) which are generated along with the creation of bubbles, and then, the structure is arranged to prevent such back waves because the back waves result in the energy loss in performing discharges. In accordance with the invention disclosed in the specification thereof, the triangle portion of a triangular plate member is arranged to face each heater that creates bubbles. The invention can suppress the back waves temporarily and slightly by means of such plate member thus arranged. However, there is no reference at all as to the correlations between the development of bubbles and the triangular portion nor any idea is disclosed as to dealing with such correlations. Therefore, this invention still present the problems as given below.
In other words, the invention thus disclosed is designed to locate the heaters on the bottom of a recessed portion, thus making it difficult to provide the condition where the heaters can be communicated with the discharge ports on the straight line. As a result, each liquid droplet is not stabilized in keeping its shape uniformly. At the same time, since the development of each bubble is allowed to take place beginning with the circumference of each apex of the triangular portions, the bubble is developed from one side of the triangular plate member to the opposite side entirely. Consequently, the development of each bubble is completed in the liquid as has been usually effectuated as if there were no presence of the triangular plate members. Here, as to the bubble development, therefore, the presence of the plate members has no bearing at all. On the contrary, the entire body of each plate member is embraced by each bubble, and in the stage where the bubble is contracted, this condition may bring about the disturbance in the refilling flow to each of the heaters located in the recessed portion. As a result, fine bubbles are accumulated in the recessed portion, which may disturb the principle itself with which to perform discharges on the basis of the development of bubbles.
Meanwhile, in accordance with the EP-A 436047, an invention has been proposed to alternately open and close a first shut off valve arranged between the area in the vicinity of discharge ports and the bubble generating portion, and a second valve which is arranged between the bubble generating portion and the ink supply portion in order to shut them off completely (as shown in FIGS. 4 to 9 of the EP-A 436047). However, this invention inevitably partitions each of the three chambers into two, respectively. As a result, the ink that follows the liquid droplet presents a great trailing at the time of discharge, which creates a considerable amount of satellite dots as compared with the usual discharge method where the development, contraction, and extinction are performed for each of bubbles (presumably, there is no way to effectively utilize the resultant retraction of meniscus in the process of the bubble disappearing). Also, at the time of refilling, liquid should be supplied to the bubble generating portion following the disappearing of each bubble. However, since it is impossible to supply liquid to the vicinity of the discharge ports until the next bubbling takes place, not only each size of discharge liquid droplets varies greatly, but also, the frequency of discharge responses becomes extremely smaller. Therefore, this proposed invention is far from being practical.
On the other hand, the applicant hereof has proposed a number of inventions that may contribute to the performance of effective discharges of liquid droplets, which use the movable member (the plate member or the like that has its free end on the discharge port side of its fulcrum unlike the conventional art). Of the inventions thus proposed, the one disclosed in the specification of Japanese Patent Application Laid-Open No. 9-48127 is such as to regulate the upper limit of the displacement of the movable member in order to prevent even a slight disturbance of the behavior of the movable member disclosed in the specification of Japanese Patent Application Laid-Open No. 9-323420. Also, in the specification of Japanese Patent Application Laid-Open No. 9-323420, there is the disclosure of an invention that the position of the common liquid chamber on the upstream of the aforesaid movable member is arranged to be shiftable to the downstream side, that is the free end side of the movable member, by the utilization of the advantage presented by the movable member so as to enhance the refilling capability. However, for these inventions, no attention has been given not only to each individual element of bubbling as a whole which is concerned with the formation of the liquid droplet, but also, to the correlations between each of them, because in the premises set forth for the designing the invention, the mode has been adopted so that the bubble is released to the discharge port side at once from the state where the development of the bubble is temporarily embraced by the movable member.
Then, in the next stage to follow in this respect, the applicant hereof has disclosed in Japanese Patent Application Laid-Open No. 10-24588 the invention that a part of the bubble generation area is released from the movable member as a new devise (acoustic waves) with the attention given to the development of bubble by the application of the propagation of pressure waves, which constitutes the element related to the liquid discharges. However, for this invention, too, the attention is given only to the development of each bubble at the time of liquid discharges. As a result, each individual element related to the formation of the liquid droplet itself, with which bubbling is concerned as a whole, nor the correlations between each of them is taken into consideration in giving such attention. Although it has been known that the front portion (edge shooter type) of the bubble created by means of the film boiling exerts a great influence on the discharges, there is no invention in which attention has ever been given to this portion so as to make it effectively contributive to the formation of discharge liquid droplet. The inventors hereof have ardently studied this portion in order to elucidate it technically when designing this invention.
From the viewpoint of the formation of discharge liquid droplets, the precise analyses are made as to the processes from the creation of each bubble to the disappearing thereof. Then, a number of inventions are designed as a result of such precise analyses. The present invention is one of them thus devised for the reduction of the satellites which are characteristic of ink jetting, and which tend to lower the quality of prints, and also, cause the apparatus itself and the recording medium to be stained. As compared with the conventional art, the present invention makes it possible to attain an extremely high technical standard with respect to the stabilization of the image quality in the execution of the continuous discharge operation.
The main objectives of the present invention are as follows:
A first object of the invention is to provide an extremely novel liquid discharge principle under which the created bubbles and the liquid on the discharge port side thereof, as well as the liquid on the supply side, are suppressed by the movable members and the structure of the entire liquid flow paths.
A second object of the invention is to provide a liquid discharge method and a liquid discharge head with which to design the reduction of satellites by controlling the discharge liquid droplet forming process, and at the same time, to substantially eliminate the satellites in the discharge operation.
A third object is to lighten the system load of the structure needed for the recording apparatus to make it possible to remove the drawbacks resulting from the presence of satellites and the fluctuation of meniscus.
In order to achieve these objects of the present invention, the liquid discharge head comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubbles; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, the regulating portion is arranged to face the bubble generating area in the liquid flow path, and then, with the essential contact between the displaced movable member and the regulating portion, the liquid flow path having the bubble generating area becomes an essentially closed space with the exception of the discharge port.
Also, the liquid discharge method of the invention that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the step of placing the movable member to be in contact with the regulating portion before the bubble being bubbled to the maximum to make the liquid flow path having the bubble generating area essentially closed spaces with the exception of the discharge port.
Also, the liquid discharge method of the invention that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; and a liquid flow path communicated with the discharge port having a bubble generating area for enabling liquid to create bubble, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of discharging the liquid from the discharge port in the state of the liquid column by creating the bubble in the liquid by the application of the thermal energy; making the amount of liquid shift to the bubble generating area larger on the downstream side than the upstream side in the bubble generating area in the earlier stage of bubble disappearing before the liquid column is separated; and drawing the meniscus into the discharge port to separate the liquid column for the formation of the liquid droplet.
Also, in order to achieve the objectives discussed above, the liquid discharge heads of the invention are designed as follows:
A liquid discharge head comprises heating members for generating thermal energy to create bubbles in liquid; discharge ports forming the portions to discharge the liquid; liquid flow paths communicated with the discharge ports, at the same time, having bubble generating areas for enabling liquid to create bubbles; movable members arranged in the bubble generating areas to be displaced along with the development of the bubbles; and regulating portions to regulate the displacement of each of the movable members within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge ports. Then, the area connecting the range from the end of the heating member on the discharge port side to be central portion with the center of the discharge port is in the linearly communicated state where only the liquid can be present, and the free end of the movable member is positioned to face the central portion of the bubble generating area when the movable member is on standby, and then, with the essential contact of the free end with the regulating portion, the component of the maximum bubble on the upstream side is formed substantially in a uniform state by producing the maximum flow path resistance of the flow path on the upstream side of the bubble generating area.
Also, a liquid discharge head comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. Then, for this liquid discharge head, the regulating portion is arranged above the bubble generating area in the liquid flow path, and bubble carrying mechanism is provided to carry bubble in the liquid flow path by creating liquid flow from the gap between the movable member and the regulating portion along the liquid flow path facing the heating member in the disappearing process of the bubble.
Also, a liquid discharge head comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. Then, with the essential contact of the movable member with the regulating portion, the liquid flow path having the bubble generating area of this liquid discharge head become essentially closed space with the exception of the discharge port, and when the movable member opens the essentially closed spaces, liquid flows in the bubble generating areas, and the flowing-in liquid join the liquid shifting to the heating member side along with disappearing in the area between the discharge port and the heating member.
Also, a liquid discharge head comprises a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge head, preliminary displacing means is provided for displacing the movable member independent of the development of the bubble, and the regulating portion is arranged to face the bubble generating area in the liquid flow path, and with the essential contact of the movable member with the regulating portion, the liquid flow path having the bubble generating area become essentially closed space with the exception of the discharge port, and when the movable member opens the essentially closed space.
Also, a liquid discharge head comprises a heating member for heating liquid in a liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the liquid flow path in a cantilever fashion supporting one end thereof with the free end positioned on the discharge port side; a regulating portion to regulate the displacement of the movable member by being essentially in contact with the movable member when the movable member is displaced along with the development of the bubble to close the upstream side of the liquid flow path substantially; and controlling means for controlling the driving of the heating members. For this liquid discharge head, the controlling means performs the driving of the heating member for the next liquid discharge during the movable member is displaced in the direction toward the displaced state before the vibrations of the movable member is settled completely in being restored from the displaced state subsequent to the last liquid discharge when liquid is discharged from the same liquid path continuously.
Also, a liquid discharge head comprises a heating member for heating liquid in a liquid flow path to create bubble in the liquid; a discharge port communicated with the downstream side of the liquid flow path for discharging the liquid by the pressure along with the development of the bubble; a movable member arranged in the liquid flow path in a cantilever fashion supporting one end thereof with the free end positioned on the discharge port side; regulating portions to regulate the displacement of the movable member by being essentially in contact with the movable member when the movable member is displaced along with the development of the bubble to close the upstream side of the liquid flow path substantially; and controlling means for controlling the driving of the heating member. For this liquid discharge head, the controlling means performs the driving of the heating member for the next liquid discharge during the movable member is displaced in the direction toward the initial state before the vibrations of the movable member is settled completely in being restored from the displaced state subsequent to the last liquid discharge when liquid is discharged from the same liquid path continuously.
Also, a liquid discharge head comprises a discharge port for discharging liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the liquid flow path to face the bubble generating area, having a free end on the downstream side with respect to the liquid flow in the direction toward the discharge port; and a fluid control portion arranged in the vicinity of upstream side end or on the more upstream than the upstream side end of the bubble generating area facing the bubble generating means in the liquid flow paths to control the liquid flow from the discharge ports toward the bubble generating area, and the movable member being essentially in contact with the fluid control portion by the displacement of the movable member along with the development of bubble in the bubble generating area.
Also, in order to achieve the objectives discussed above, the liquid discharge methods of the invention are as follows:
A liquid discharge method that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port. For this liquid discharge method, the area connecting the range of the heating member from the discharge side end to the central portion with the center of the discharge port is in the linearly communicated state where only liquid can be present, and the movable member having the free end positioned to face the central portion of the bubble generating area when the movable member is on standby, and with the free end being essentially in contact with the regulating portion, the maximum flow path resistance is formed in the flow path on the upstream side to discharge the liquid in the state of the component of the maximum bubble on the upstream side being uniformalized substantially.
Also, a liquid discharge method that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable members within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, and also, the regulating portion being arranged above the bubble generating area in the liquid flow path, comprises the step of shifting the bubble in the liquid flow path by creating the liquid flow from the gap between the movable member and the regulating member along the plane facing the heating member at the time of disappearing the bubble.
Also, a liquid discharge method that uses a liquid discharge head provided with: a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubbles; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of forming substantially closed space in the liquid flow path having the bubble generating area therein with the exception of the discharge port when the movable member is essentially in contact with the regulating portion before the bubble is bubbled to the maximum; enabling liquid to flow into the bubble generating area when the movable member opens the substantially closed space; and joining the flowing-in liquid with liquid shifting to the heating member side along with disappearing bubble in the area between the discharge port and the heating member.
Also, a liquid discharge method that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; and a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the step of joining fluid shifting from the discharge port side to the heating member side along with the disappearing of the bubble with fluid shifting from the upstream side of the heating member to the discharge port side between the discharge port and the heating member.
Also, a liquid discharge method that uses a liquid discharge head provided with a heating member for generating thermal energy to create bubble in liquid; a discharge port forming the portion to discharge the liquid; a liquid flow path communicated with the discharge port and having a bubble generating area for enabling liquid to create bubble; a movable member arranged in the bubble generating area to be displaced along with the development of the bubble; and a regulating portion to regulate the displacement of the movable member within a desired range, and with energy at the time of bubble creation, the liquid being discharged from the discharge port, comprises the steps of providing preliminary displacing means for the liquid discharge head for displacing the movable member independent of the development of bubble, and displacing the movable member using the preliminary displacing means before the development of bubble; and placing the movable member to be in contact with the regulating portion before the bubble being bubbled to the maximum to make the liquid flow path having the bubble generating area essentially closed space with the exception of the discharge port.
Also, a liquid discharge method comprises the steps of heating liquid in a liquid flow path to create bubble in the liquid for the development thereof; displacing a movable member in a cantilever fashion supporting one end thereof in the liquid flow path from the initial state thereof along with the development of bubble; closing the upstream side of the liquid flow path with the movable member when the bubble presents the maximum volume thereof, and discharging the liquid from the discharge port by pressure along with the development of bubble; and restoring the movable member to the initial state from the displaced state along with the disappearing of the bubble after the discharge of liquid. For this liquid discharge method, the driving of the heating member is initiated for the next liquid discharge during the movable member is displaced in the direction toward the displaced state before the vibrations of the movable member is settled completely in being restored from the displaced state subsequent to the last liquid discharge when liquid is discharged from the same liquid path continuously.
Also, a liquid discharge method comprises the steps of heating liquid in a liquid flow path to create bubble in the liquid for the development thereof; displacing a movable member in a cantilever fashion supporting one end thereof in the liquid flow path from the initial state thereof along with the development of bubble; closing the upstream side of the liquid flow path with the movable member when the bubble presents the maximum volume thereof, and discharging the liquid from the discharge port by pressure along with the development of bubble; and restoring the movable member to the initial state from the displaced state along with the disappearing of the bubble after the discharge of liquid. For this liquid discharge method, the driving of the heating member is initiated for the next liquid discharge during the movable member is displaced in the direction toward the initial state before the vibrations of the movable member is settled completely in being restored from the displaced state subsequent to the last liquid discharge when liquid is discharged from the same liquid path continuously.
Also, a liquid discharge method comprises the steps of using a liquid discharge head having the fluid controlling portion as referred to in the preceding paragraph; and dispersing the flow of liquid on the upstream side of the fluid control portion in the bubble disappearing process when the movable member parts from the fluid control portion.
Also, in order to achieve the objectives discussed above, the liquid discharge apparatus of the invention comprises a liquid discharge head as referred to in any one of the preceding paragraphs of this summary in which the liquid discharge head of the present invention is particularly described; and means for carrying a recording medium to carry the recording medium that receives liquid discharged from the liquid discharge head.
With the valve mechanism of the movable members of the liquid discharge head of the present invention, it possible to suppress the back waves, that is, the liquid shift in the upstream direction along with the pressure waves in the direction toward the upstream side, and at the same time, with the meniscus which is drawn into the discharge port rapidly, it becomes possible to prevent the satellites, hence stabilizing the discharge amount of liquid for the enhancement of the quality of prints.
Particularly, with the structure designed for the present invention where the trailing portion that forms the liquid column by being connected with the discharged liquid droplet is cut off from the meniscus quickly, the stabilization of the liquid droplet formation can be attained, hence making the higher quality recording possible.
Other objectives and advantages besides those discussed above will be apparent to those skilled in the art from the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part hereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention.
In this respect, the term xe2x80x9cupstreamxe2x80x9d and the term xe2x80x9cdownstreamxe2x80x9d used in the description of the present invention relates to the direction of the liquid flow toward the discharge ports from the supply source of the liquid by way of each of the bubble generation areas (or each of the movable members) or represented as expressions related to the structural directions.
Also, the terms xe2x80x9cdownstream sidexe2x80x9d related to the bubble itself means the downstream side in the flow direction described above or in the structural directions described above, or it means the bubble created in the area on the downstream side of the area center of each heating member. Likewise, the term xe2x80x9cupstream sidexe2x80x9d related to the bubble itself means the upstream side in the flow direction described above or in the structural directions described above, or it means the bubble created in the area on the upstream side of the area center of each heating member.
Also, the expression xe2x80x9cessentially in contactxe2x80x9d between each of the movable members and the regulating portions used for the present invention may be the approaching state where liquid of approximately several xcexcm exists between each of them or the state where each of the movable members and the regulating portions are directly in contact.